''Do you eat dead crab, Aunty Bee?” asked my niece one day, as I was about to tuck into some particularly succulent crab cakes. (Her mother, my sister, is a vegetarian.) And I had to admit that, yes, I do eat dead crabs, and dead chickens and pigs and even dead lambs and I enjoy them all very much. But this has been a year, if ever there was one, to make any carnivore question the habit.

In January we reeled at the “horsegate” scare: the discovery that numerous cheap “beef” products were adulterated with horsemeat, in a trade stretching from Ireland to France to Romania. Then, in August, we were offered a slightly alarming glimpse of the future of meat. After two years and a quarter of a million pounds, a Dutch scientist created the first hamburger from lab-grown meat. The meat, which looked mottled, was grown from stem cells from a cow’s shoulder. A food critic pronounced the burger close to meat “but not that juicy”.

Juicy or not, I find the whole idea of lab-generated meat creepy. But the mere fact that it exists should give us pause. It’s obvious – and not just to vegetarians – that the world’s meat-eating is unsustainable. Consumption of meat worldwide is forecast to double by 2050. And we already eat far too much. As Alex Renton writes in his pithy e-book Planet Carnivore (Kindle, £1.99), in Britain most people consume the equivalent of their own body weight in meat every year. Globally, industrially reared animals use up enough cereal to feed three billion people.

Forgive me if this seems a strange moment to raise the subject. In the run-up to Christmas, my own house is awash with delicious meats. Apart from the turkey (bronze), which will be stored in the garden shed, because it’s too big for the fridge, I lay in a ham for Boxing Day. We’ll get a rib of beef for New Year and maybe I’ll make a game casserole or two. It is worth asking, though, why we feel the celebration is not complete without all this meat. In his 2009 book Eating Animals, Jonathan Safran Foer questioned the idea that turkey was a necessary part of Thanksgiving. He argued that the tradition would not be “broken” if people simply ate all the fixings: “the sweet potato casserole, homemade rolls, green beans with almonds… buttery mashed potatoes”. Speaking for myself, much as I love the roast potatoes and chestnut stuffing and sprouts, I do feel the meal wouldn’t be the same without the symbolic bird at its centre. Not to mention the gravy!

At least at Christmas we recognise the meat as special. The real problem is all the other days. The most helpful thing I’ve yet read on the future of meat eating is the diet book VB6 by Mark Bittman (Sphere, £12.99). Bittman makes the case – both for our health, and that of the planet – for being vegan until 6pm every day, and then eating anything you like, within reason. I’d prefer it to be vegetarian than vegan, but what I love about this book is its pragmatism. Bittman is not saying we should never eat steak, or turkey on Christmas Day. His point is that, when it comes to eating meat, “Any reduction is better than none.”